This invention relates to an improved method for preparing a textile-treating composition comprising a durable press resin and a silicone emulsion and to improved compositions useful therein. More particularly, this invention relates to a process comprising preparing a homogeneous blend of a concentrated aqueous solution of a durable press resin and a concentrated aqueous emulsion of a hydroxy-endblocked polydimethylsiloxane thereby improving the resistance of said aqueous emulsion to skin over during storage when exposed to the atmosphere, and thereafter preparing a textile-treating composition using the blend.
Herein, the concentrated aqueous solution of durable press resin may also be denoted as the concentrated resin solution and the concentrated aqueous emulsion of hydroxyl-endblocked polydimethylsiloxane may also be denoted as the concentrated silicone emulsion. A mixture of the concentrated resin solution and the concentrated silicone emulsion may also be denoted herein as the concentrated homogeneous resin-silicone blend.
Durable press resins and silicone compositions have been individually used for a long time to provide improved properties of textiles. In addition, to further improve the physical properties of textiles treated with durable press resins, silicone materials have been combined with durable press resins to soften the durable press resin and thereby provide improved hand, tear strength, and abrasion resistance of the treated textile. Specifically, Rooks has reported in the Journal of the American Association of Textile Chemists and Colorists 4(1), 14-15 (1972) that the addition of 1 percent of a silicone emulsion polymer to a textile-treating bath comprising a dimethyloldihydroxyethylene urea durable press resin served to fortify the durable press performance of a polyester/cellulose textile treated therewith.
Preparation of a textile-treating composition comprising a silicone component and a durable press resin is usually done immediately prior to its intended use using concentrated forms of the durable press resin and silicone component. Thus, a common method of preparing a textile-treating composition comprises adding a concentrated aqueous solution of a water-soluble durable press resin and a concentrated aqueous emulsion of a hydroxyl-endblocked polydimethylsiloxane, either sequentially or simultaneously, to a portion of water, preferably containing a surfactant, to provide a composition having suitable stability and proper dilution for applying to a textile. Preparing a textile-treating composition immediately prior to use, for example within 8 to 10 hours of its intended use, is necessitated by the fact that the completed bath also usually comprises catalysts and curing agents for the durable press resin and the silicone component, thereby rendering the rextile-treating composition unstable to long term storage. However, there are some disadvantages with this process.
A principal disadvantage with the above method for preparing a textile-treating composition is the tendency of the concentrated silicone emulsion to skin over when it is exposed to the evaporating action of the open atmosphere. This skin-over results in the formation of a semi-solid or solid layer of silicone polymer on the surface of the emulsion and on the sides of its container. A principal disadvantage of this skin-over is the tendency of this layer of semi-solid or solid polymer to be incorporated into the subsequently prepared textile-treating compositions as non-colloidal particles which interfer with the proper use of the textile-treating composition. It can be seen that a method of reducing or avoiding this skin-over would be advantageous, especially if the method were simple, effective, and economical.
Another disadvantage with the above method for preparing a textile-treating composition is the need to prepare, ship, store, inventory or otherwise handle the several individual components that are used in preparing the textile-treating compositions. It would be desirable to combine two or more of these individual components to form stable concentrated blends to facilitate and simplify said handling.
Yet another disadvantage with the above-mentioned method for preparing a textile-treating composition is the possibility for error and batch-to-batch variation when admixing several components "in the field"; that is, in the relatively less-sophisticated environment of the end-user. This possibility for error and batch-to-batch variation can be reduced by doing some of the mixing of components at the component manufacturer's and/or supplier's facility.